1. Field of the Invention
This invention relates to a power division system which includes hydraulically interconnected planetary gear assemblies for dividing and transferring rotational power to two or more output shafts rotatable at speeds differing from one another. The invention is particularly useful as a modular power distribution system for vehicles having multiple drive axles.
2. Description of the Prior Art
Tandem axle trucks and other vehicles having two drive axles are normally provided with either a bevel or planetary gear differential system for dividing and transferring rotational power from the engine to each of the drive axles. Systems of this type are known to function in a reasonably satisfactory manner for on the road and off the road vehicles.
It is possible to design a power division system using only gears to drive more than two drive axles in unison while applying equal torque to all axles. In practice, however, such systems are relatively complicated and bulky and are not practical for normal use.
Moreover, known power division systems consisting primarily of gears cannot be constructed to easily permit the addition or deletion of drive axles to an existing vehicle in a manner such that the system in use applies equal torque to all of the axles at all times even though the relative velocities of the axles may differ. Typically, the entire drive system must be redesigned from the front to the back if the operator wishes to add or remove a drive axle.
As can be appreciated from the foregoing, there is a need in the art for a versatile and efficient means of dividing rotational power from a power source between two or more separate work destinations or secondary driveshafts which may rotate at speeds slightly different from one another as may occur, for example, when tires of unequal diameter are mounted on the axles. Moreover, it would be desirable to provide a power division system that may be easily modified by increasing or decreasing the number of drive axles without undue labor or expense.